ID:               45030
 Updated by:       [EMAIL PROTECTED]
 Reported By:      lieyang at yahoo dot com
-Status:           Open
+Status:           Assigned
 Bug Type:         GD related
 Operating System: x86_64 GNU/Linux Kernel 2.6.9-4
 PHP Version:      5.2.6
 Assigned To:      pajoye
 New Comment:

Pierre, the fix worked, commit?


Previous Comments:
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[2008-05-29 21:07:49] lieyang at yahoo dot com

We have verified the fix resolved our problem. Thank you very much! Do
you have any estimate on when the fix will make into the stable branch?

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[2008-05-18 18:12:32] [EMAIL PROTECTED]

Right, there is a alpha values between 0 and 2. This is a little
rounding issue in the interpolation function.

As it is not relevant when you use the full range of the 8bit (7bit in
gd 2.0.x internals), it could cause some troubles when you introduce
more errors while using only 4bits. 

The worst case will end with an error twice bigger than the original
one. That's certainly why you see the little black pixels.

Here is an attempt to minimize the error in the edge of the alpha
values:

http://pierre.libgd.org/patches/bug45030.txt

It should fix non obvious errors like the one you had.



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[2008-05-18 16:14:25] lieyang at yahoo dot com

You can see the noise on both my 56x56 image and image generated from
Rasmus's reproducing code sample with resizing from 90x90 to 50x50 (I am
not talking about the anti-aliasing areas :)

GIMP: Tools > Selection Tools > By Color select, click a few spots in
the empty region of the image and you will see the noise being
selected.

Paint.net: use the color select tool and click a few times on the empty
region of the image, some pixels will display the transparency as 2.

(thank you so much for your quick response!)

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[2008-05-18 10:29:14] [EMAIL PROTECTED]

The 56x56 image looks perfectly fine to me. I also checked the alpha
values for the translucent areas and they look fine too (full
translucent when they are not near the star anti aliased pixels, as
expected).

To see how is the alpha channel in the result image, please look at
this zoomed version of the alpha channel only:

http://pierre.libgd.org/bugs/45030_alpha_only.png

100% black means opaque and the gray squares are only to show a
background (what would be behind the image). As you can see, there is no
noise in the transparent areas.

Are you sure that there is not a bug in the Motorola display system?
Maybe it does not support semi transparent pixels.

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[2008-05-18 03:51:39] lieyang at yahoo dot com

Here are my test source image (png 90x90): http://tinyurl.com/65tdtm
Resized to 56x56 with noise in alpha channel: http://tinyurl.com/6yold7

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the rest of the comments, please view the bug report online at
    http://bugs.php.net/45030

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